Problems Raising Existing Ceiling Joist And Attaching To Roof Rafters
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- Опубликовано: 11 сен 2024
- www.homebuildin... Click on this link for more information about home remodeling, repairs and building. Here's another question that was sent to me and I thought it would be helpful for other viewers interested in figuring out whether or not they could raise their existing ceiling. This video involves a few tips about whether or not you can add additional weight to existing roof rafters.
good video. I have a 26 foot wide span with a 4 foot high peak, lifting ceiling from 8 foot to 9.5 foot (one-third of the peak). My structural engineer instructed to sister 2x10s alongside the rafters and then use 2x6s to cross-tie the rafters. There's a bit more than that, ie, gussets and nails, but this info is just to give a general idea of what the job entails. Also, do not remove the existing trusses until the rafter cross-ties are completed.
thanks for the info, im doing a similar project. One question for you, did he require you to cross-tie the rafters at the upper or lower 1/3?
@@Wigwhom86 lower 1/3, and then the bottom of the cross tie is the new ceiling level when sheet rock is installed..
@@Wigwhom86 but definitely get a structural engineer or architect involved. I am neither and do not want to steer you wrong.
@@dcfunhouse of course, just educating myself on whats possible.
DC Funhouse what was the size of your existing rafters that had to sister on to?
Thanks for the videos, helpful to get some ideas. Glad to see someone doing videos like this 👍👍
I have a 2 car garage . Old put swing doors and no header. I do alot of framing and general construction and have been considering doing this to fit my work truck in the garage . My idea onto of moving ceiling up is using a wire rope and applying tension in a cross cross manner form one side to center of collar down the center and to the opposite side I figured this wire rope and turn buckle tension system with the right hardware and know how could be an effective solution to keeping the walls from moving out and having the ridge beam to fail and bow in center
My dad did this to his garage and its been like this for like 20 years or more and its about 16 feet, He also moved garage up against house and years ago he said they denied the permit twice then he got drunk and did it up and it passed
You also have to make sure your rafters are sized large enough. Based on the height, you have a factor change on on rafter span. Basically, it shortens the span based on the height raised.
Raising the roof sounds dangerous, good video, thumbs up.
it's not raising the roof, it's raising the ceiling. Big difference.
Could you double up a small section of the rafter from the bottom of the new rafter tie to the top plate? If you had a 2x6 rafter you could even rip a 2x8 to an exact size to completely cover top plate. Make it easier to drywall as well. Thoughts?
I’ve read the comments.
That is a ceiling joist or rafter tie.
It’s not a bottom chord like you have on a engineered truss.
You can raise the ceiling joist no higher than 1/3 the total length of the rafter to the outside building line.
If you do than a structural ridge beam is needed. With an engineered ridge beam and engineered calculations you can eliminate the ceiling joist.
If the pitch is 3/12 and under a ridge beam is needed no matter what.
In this case let’s say this was a 4/12 and building was 16 feet wide the minimum ceiling joist would be a 2x4 raised to a height no more than 1/3 the length of the rafter.
The ceiling joist is there for dead load and not to be confused as a collar tie.
I didn't see a question, but just in case there was and I missed it, feel free to ask it again.
Excellent points made. Thx much.
Very welcome
So how would you do it? I do have about 25’ span. The town engineer said I can raise the rafters within the first 1/3, however , that doesn’t seem correct as you put it. How could I tie the raised rafter to the existing wall to help support the weight without sag on the roof and without pressure to the wall? I am a homeowner that will be doin the work. Thank you for the video!
What if you did this with just one ceiling joist out of a 60x40 building that has rafters every 6'? I want to run a lift between the rafters (same direction as the rafters). So If I raise just one I would have 12' between normal rafters to run the lift.
Can I take out every other floor joist? There are only five l l l l l and I want to remove 3 of them, the two outer ones and the center one removed so it's just 2 remainin l l is that enough to keep outer walls up??
I think the truss strength would be sufficient provided the truss was crippled. But I agree with you losing your tensile strength wall to wall.
Just right off the bat, I'm not engineer, but that visually it doesn't square with me. I should think that most people could look at that and go "something looks very wrong there"... leaving rafters unsupported like that to carry the load of the ceiling seems like a bad idea without additional support. It's all about stress lines (as you well know!). Just moving joists up into the rafters concentrates who knows how much extra load on the ends of rafters that was shared by the joists before. I would think that you _could_ do this if you added additional vertical supports and then anti-twisting measures for the rafter ends. Relieve the stress with uprights.
It's definitely good to take a common sense approach to construction, but it would be even better to use information that has been tested or approved by local building authorities.
Reverse question: What if the ceiling is too high. Can you remove the ceiling joist and build a floor 4-5ft down the walls and have some way to support the roof properly while keeping it open to have a loft space?
So to prevent the rafters from sagging you need 2 things...
1. put 3/4 plywood at the peak of every truss, cut to fit. Make sure the plywood comes down at least 16 inches. Glue, screw each piece....install a piece on each side of the truss. This stop any movement of the truss.
2. Plus also glue a 2 X 4 to the bottom of each 2 X 6 rafter making it a 2 X 10. Glue and screw 3/4 plywood to each side. Now you have a 3 inch thick truss that is glued and screwed allowing for more weight. As long as your truss is bird gaged over outside walls, the outside walls will not move.
Can you do a video on removing the ceiling drywall as well as some of the ceiling joists (to a gap of 32-48” OC), and then drywalling over the roof rafters in order to get a vaulted look without installing a ridge beam?
I will put it on my list of future videos.
Much appreciated!
@@gregvancom do you have that video available?
Did you make that video???
There is nothing inherently wrong as long as the members are properly sized. The loads are surprisingly low too. Most people imagine they are worse than they are. Take a 16' wide building with a 4/12 pitch, shingle roof as an example. If you raise the bottom chord such that it is only 14' long, the point load on the top member at the connection point is only 128#. If you then calculate the additional load on the rafter, it increases bending stress by 18%, and deflection by 14%. considering they are already 100%+ overdesigned assuming a 2x6 SYP member, there is absolutely no reason this can't be done.
But then again, I've designed thousands of buildings and can run the numbers in my head most of the time.
Great points and thanks for reiterating. If you know that the lumber used in the existing structure can support the modifications then it shouldn't be a problem.
I wonder if I could hire you to help me out.
I need to raise one end joist or cut that section out to provide more head room for steep stairs. (Extend stairs out so not so tall) there is a supporting wall on each side of staircase. What's your thoughts on this? I would box out the new headroom and hopefully support the missing section of joist another way. Thanks
I have a second story 8 ft ceiling that I want to tturn into a 10 ft tray ceiling. Can it be done reasonably? Can I support the ceiling joists and cut out my ceiling area and frame the ends and support that with 2x4s to the rafters? The room is 20x14 but all I want trayed is 10 x 10 area .
I can't answer for sure, but if the tray ceiling can be remodeled to fit into your existing house, then it shouldn't be to difficult.
Hey Greg I am a young contractor what's the software your using to design build, it looks like a great software
This is exactly what I want to do in my garage I have trusses right now.. garage is 40 feet long by 25.
I was thinking about putting in 2 by 8 with collar ties and plywood to attach from the collar ties to the top half of the Rafters that is glued in all screwed together and then remove the old 2 by 4 trusses
From 8 foot ceiling to 11 feet in the middle.
Would that prevent the walls from being pushed out? I won't be removing all of them just about 18 ft in the centre
I wish I could provide you with an answer, but I cannot provide any type of structural engineering advice. However, if you draw a diagram of what you're trying to do or send me some pictures, I can provide you with an educated opinion.
@@gregvancom . What is your email
Never use screws for framing unless specifically required by the engineering.
Turn the joists and rafters into scissor trusses. You don't get the ceiling height across the entire width, but it is better structurally.
Add a beam on each side under the newly raised ceiling joists. Those beams will need to be supported on both sides.
I had a similar situtation I ran a steel raj from gable to gable and butted the new feeling choices into it I then braced the ridge board from the raj with 4x4's every 48 inches thus preventing the drop of ridge beam or rafters as the ceeling choices were butted jus into the rsj rafters can vary more weight if the ridge beam is supported from a solid support and my wall span was 20 ft
what if the exterior walls are 16" x 8" blocks? and not stud wall? will raising the ceiling be easier then?
It might be, but I don't have any videos on that yet.
Best saw to cut through the existing joists?
What if you go with a coffered ceiling look
There are tables in the IRC code for this. The allowable span for the rafters is decreased by a factor depending on how high you raise the joist. The higher you raise the joist, the more the rafter span for a given rafter size is reduced.
Can you provide us with the page or reference numbers and year of International Residential Building Code Book?
@@gregvancom I was looking in the Oregon Residential Code (I live in Oregon), which is derived from the IRC, but the tables are the same. Table R802.5.1 lists the rafter spans. The "rafter span adjustment factor" table is at the end. If the joists/ties are raised up 1/3 of the height, the allowable rafter span is reduced by a factor of .67; i.e., the rafter can only span 2/3's the width it ordinarily could. That's a lot of reduction.
BTW, 1/3 is the highest amount listed on the table. So perhaps that's where the notion comes from that you can raise the joists up to that height. You can, but it reduces the allowable building width, or greatly increases rafter depth. In other words, usually not practical for retrofitting purposes. I happened to look this up because I'm raising my joists a few inches to make additional room for an opener; in my case the existing rafters just barely are sufficient.
Does not ad too much extra weight to the rafters, just the drywall and ceiling joist weight.
Certainly the rafters, sheathing, roof material greatly exceed the ceiling weight. As well, the snow load will still be supported by the rafters .... no change there.
I have a 20x30 garage. I want to raise the ceiling on the front section only of the garage only. So the first third of the garage. Is this still a bad idea even though the rest of the garage will be left alone. Need higher ceiling for a golf simulator 😉
No, you do it.
"Tough tooglie-woogies" 😂😂😂
I wanna raise my ceiling either to a vaulted or just raise it 2ft. In diagram add a wall don the middle which is my load bearing wall. Giving each side a 12ft room. the left side is the side I wanna raise the ceiling. giving that room a bigger feel. thus house originally built in the 30,s. Could I put a 2ft wall on top of the load bearing wall then run the ceiling joist from there to roof joist?
to add..we don't get heavy snow 1-2inches is very rare. has shingles. which going to do a total tear off and go back with a metal roof.
You might be able to, but you would need to contact the structural engineer for clarification. I would hate to give you tell you you could and then have your house collapse.
thanks for the video
Can you do this and then put a beam above the ceiling ties? And tie it on the ends on a wall?
I would need to see a drawing or a picture of what you're referring to or more detailed information.
Interesting video. Keep in mind if its just drywall the added weight is spread out over all the rafters so its not as much weight as you think
Your comment could be confusing to other viewers. For example if I had a larger ceiling, then the weight of the drywall could make a bigger difference in the structural weight transfer than a smaller one. Let me know if this doesn't make sense.
It’s in the code book how and when you can do this pretty simple.
Can you provide the building code reference or page and book information?
@@gregvancom can’t really send a real book to you but send me your email and I can reference you to the code book for my state i and you can head down to the building department and ask for the code book of you state and you can get a photo copy of the pages. Should be the 2016 booklet.
Can I slant a ceiling one way up towards the pitch of the roof. My house is just a rectangle and One end of my living room is at the pitch of my roof.
If you're asking if you can raise one end of the ceiling joist to create a slanted or sloped ceiling, then probably not, because the ceiling joists are used to connect the walls together and prevent them from leaning.
could you use scissors trusses to raise ceiling?
the rafter will crack where the new joint is. i've seen it both from heavy snow load & straight line downdraft winds
Interesting and thanks for leaving the comment. Snow loads and wind would definitely need to be addressed for this type of situation.
Two possible thoughts - I mentioned this in another video regarding a ridge beam, but I am a big fan of LVLs - I wonder if you either sister them to rafters (possibly every other) and/or run gable to gable mid-span supporting beams, possibly forming a 90 on TOP of raised deck? cut small birds mouths for bearing and tie all together w/hurricane clips. would have to have point load support down gable wall, and a gable vent through which you could feed the absurdly long LVLs, but it could work. Maybe I am overthinking this :)
What if there was a center parallel wall dividing the house and supporting the new elevated ceiling rafters?
If the wall is located in the center and can be used in the same way a ridge beam can be used, then you might be able to use the wall. The wall also might need have a structural concrete footing or some type of structural supports under it also.
With joists raised as you show, adding then corner buttresses, as often seen at the wall end of church gables, would help both the tie problem and the transfer of joist load back to the wall-top plates. The extra turning moment at the corners can be compensated with welded metal-work braces mating the buttresses, and by doubling-up the wall studs. A lot of interior wall material has to be broken out for this method anyway, so doing the extra clearing for reinforce studs (down at least 3 X the drop of a corner buttress - the cantilever rule of thumb) my not bother some people, will provide new electrical lighting or fan options, and give extra work to drywallers. ;-}
Looks like another creative home repair, thanks for sharing.
If raising the ceiling makes you exceed the allowable spans from IRC tables, just sister the rafters.
The solution would to run a beam down the center supported at both ends and join the ceiling joist in the middle
The roof weight is still going to be on the exterior walls. You can brace all you want, install more wood to connect the roof trusses so they have more integrity but the weight is still transferred to the ends of the rafters and onto the wall. The key is what is the exterior wall made of? If it's brick or block attached to the wood frame, then no issue. If it's only wood exterior walls with siding, still have same issue. I don't think the weight of the roof, snow load, wind load, people walking on the roof, etc.. is enough weight to push out the exterior walls if the walls are secured properly to the floors on each level.
I have a solution for this, but they have accomplished what they have done for the last couple weeks and have been falsely rejected by their power to be tied down with the roof deck with the skirt and the new one of the wall.
using 6by 2 ridge and rafters the span is 10 ft length of building gable to gable 16 ft , want raise collar ties up to just under the ridge, , will put extra fixings at wall plates, block built construction, new build??? current
Send me some pictures of the building and you can get our email address at the website and I will see if I can help.
And even easier thing to do is just remove the nasty drywall ceiling and then you'll have all the open space above you. If you don't mind looking at the rafters from where the ceiling was hanging it shouldn't be a problem. Just paint them up and make them look good. No need to restructure the entire house if you can just remove the ceiling
Excellent point and don't forget the roof ceiling insulation.
But then you also have ceiling joists above you to look at as well!
Can you show me how to achieve this on a flat truss ceiling
Yes, feel free to send me a few pictures and a brief description of your project. Our email address can be found at our website.
What would be another way to raise ceiling joist
There are other ways, but it would depend upon the existing framing. The most common would be to remove the roof and extend the walls.
Also you are forgetting to include the force being applied to the moved ceiling joists, they are resisting the inward pressure from the roof. The raised ceiling joists aka raised rafter ties, though not perpendicular to the rafters, do provide outward force on the rafters
I'm not sure what you're suggesting, but feel free to email me some more detailed information or structural engineering calculations and I'll be glad to take a look at them.
I think he is talking about the rafter ties acting in compression to keep the rafters from sagging as well as tension to keep the walls from spreading. If the rafter ties were perfectly rigid, that would be true. If the rafter ties are going to sag under their own weight, then they just add to the problem. I am personally wondering about the best way to span 16' from ridge beam to outside walls where the rise is 20' very steep roof while using dimensional lumber that os only max 20' long. Since each rafter will require splicing or lapping two pieces I was thinking rafter ties at 4' in from the walls would work. That would be much less than 1/3 height above walls, but The extra weight pulling the rafters down sounds bad.
I am a firm believer in leaving houses as they are especially if it is an old house. Why start messing around with something that has been sitting there for 100 years... as my house has. Unless the original construction was poor, leave it. It was designed to be practical, functional and structurally sound. Most of the modifications I have seen are shoddy and the house has been ruined. If the house doesn't suit your needs, find something else.
It's difficult to argue with that point, but when remodeling or repairs or done right, there shouldn't be any problems.
bg147 I agree with you in most cases. But I actually did something similar to this on my home. Why? The ceiling was sagging and needed to be replaced. As I examined the truss structure I came to realize the ceiling was not structurally nessicary so I simply removed and vaulted the ceiling. I'm not a structural engineer but I am a mechanical engineer so I was pretty confident in what I was doing. Then I payed a structural engineer to come look at what I had already done because I decided I had better get a second opinion. He agreed that what I had done was fine but have me some great advise on other things I had done and was unsure about.
Do you want to live in a house with 7ft ceilings? No didn't think so.
That isnt a ceiling joist. That is the bottom section of the rafter assembly. It would be considered the 'bottom chord' of a truss system. Ceiling joists run in the opposite direction of the bottom chord of a truss system or a rafter system.
Hope this helps.
One thing that can sometimes be done is to build short walls that go all the way up to the rafters. This help keep your walls from separating. You can also install beams across the span, from wall to wall, like a heavy ceiling joists. It all comes down to how long your walls are, or in other words, how much support they'll need. Engineers can tell you what you need.
If you're talking about building a wall underneath the roof rafters, then it might create smaller rooms.
I'm referring to a vaulted area.
I'm still confused, are you talking about building walls on top of beams or do the walls run all the way down to the ground in the room where the ceiling is vaulted?
Short wall from floor to rafters.
Sounds good.
In Canada we have pony walls built inside the attic to transfer loads.. Raising the ceiling wouldn’t happen..
Interesting!!!! and thanks for sharing.
Where can i email you. I have a boxed house and want to vault my ceiling.
Our email address can be found at our website and there should be a link to the website in the video description box.
I was told that if you install a ridge beam, build up support on top of the load-bearing walls and then move the joists up one at a time that it can work. Obviously they would probably have to be cut down in length to match the slant of the roof, but if it is staying within the 1/3 lower level of the roof it should probably be ok. But I'm no structural engineer either.
If you built up the exterior load bearing walls then it might create a problem for the exterior roof design, but what you're suggesting should work just fine.
This seems like a problem that the scissor truss tries to solve. Although I'm not sure if that would help on a remodel.
It would definitely be difficult to install a scissor truss in an existing building.
It's a bad idea. If want to experiment, do it on an old shed.
Are you a carpenter?
According to the carpenters union I belong to, they referred to me as a journeyman carpenter. I hope this answers your question.
Not good advice. That's a general rule of thumb that doesn't apply to every situation. Good video
I rarely get comments with multiple contradicting statements like good video and not good advice, with a helpful explanation of why either one was suggested. Feel free to elaborate.
@@gregvancom I meant the 1/3rd advise at the beginning of your video.